Rawkel, how old are you, are you new in doing weights and working out? if you are it will take 1-2 years for you joints to get used to the weights; regardless, 5kg (=10lbs) is too much of an increase...only increase by about half of that (2.5kg) until you get used to it and dont feel any pain the next day; also, dont do weights using the same joints back-to-back, but take 2-3 days in between; so, if you do arms today, do lower body parts for the next 2-3 days (legs, abs, etc), then repeat; also it's important to stay regular and consistent with your workouts because the body loves routine and regularity!!!
Regards!